1. Field of the Invention
This invention relates to mechanisms for the application of herbicides and more particularly to a hand held mechanism for the selective application of liquid herbicides.
2. Description of the Prior Art
A comparatively new type of liquid herbicide has been developed which is sometimes referred to as a systemic herbicide. A systemic herbicide is one which will be absorbed by the vegetation to which it is applied and will permeate the vegetation to kill the root systems without affecting adjacent vegetation or the soil in any way. Systemic herbicide and other types of herbicides may be applied by a conventional spray method when complete destruction of all plant life in a sprayed area is desired. However, selective herbicidal tasks such as weeding operation, require that herbicides be selectively applied only to the vegetation which is to be destroyed, and this, of course, eliminates the usage of spray application techniques.
A special herbicide applicator which is designed primarily for use with systemic herbicide has been developed for use in cultivated fields and this device is in the form of a trailing wick that is attached to a tractor, or other farming mechanism. The trailing wick applicator is carried by the farm machine so as to follow the furrows between the crop plants. In this manner, the trailing wick applicator will wipe the herbicide on the weeds that are growing in the furrows only in that the trailing wick can not be allowed to come into close proximity of the crop plants. Thus, such a device is limited in its use in that it can not be employed to kill vegetation that is proximate any plants that are not to be killed, due to the fact that the trailing wick applicator can not be controlled with any degree of accuracy.
Many hand-held liquid applicators have been devised for applying various types of liquids to various items. For example, British Pat. No. 22,294, of John H. Dawson, accepted Oct. 24, 1898, disclosed an elongated tubular handle having a liquid reservoir on one end and an irregularly shaped substantially spherical sponge on its other end and disposed so as to surround liquid discharge apertures formed in that end of the tube. This device was designed for applying water to a blackboard for cleaning thereof, and is not suitable for selective application of herbicides for several reasons. First, the tubular handle of this patented device is relatively short and straight and is thus not particularly well suited for wipingly applying herbicide on low growing weeds as the user walks about an area to be treated. However, the most serious problem with this particular prior art device, and all others known to me, is leakage, or uncontrollable liquid dripping. Liquid flowing out of the delivery apertures will quickly saturate the areas of the sponge, or other wicking materials, immediately adjacent thereto and some liquid channelization occurs which results in an area or areas of excessive liquid flow usually in the form of dripping. When the prior art applicators are being employed to wipingly apply water, as is the case in the above described Dawson Patent, or other such liquids, uncontrollable liquid flow does not present any serious problems. However, this cannot be tolerated when a systemic herbicide is being used in that damage or complete loss of desirable vegetation can result.
A particular hand-held prior art herbicide applicator has been developed for selective application purposes, and that applicator is fully disclosed in U.S. Pat. No. 4,027,986. Briefly, this particular prior art applicator comprises a reservoir handle with a fill and vent control plug on its upper end and an applicator head on its other end. The applicator head is a bell-shaped enlargement which is filled with a foam rubber material and has its lower end wrapped with a carpeting material. The herbicide flows from the reservoir handle through an orifice and saturates the foam rubber and the carpeting material. Although this applicator can be used for selectively applying herbicide on vegetation, its usage is limited to a more or less dabbing type of application due to the particular head configuration. The applicator head is designed primarily for dabbingly applying the herbicide on newly cut tree trunks to kill the root systems thereof and can not practically and efficiently be used to wipingly apply herbicide to, for example, weeds which have outgrown slower growing grasses and the like, and it is awkward to use inbetween closely spaced crop plants.
Therefore, a need exists for a new and improved hand held liquid herbicide applicator which overcomes some of the short comings and drawbacks of the prior art.